This artist’s rendering shows what the redesigned interchange of Boulder City Bypass and U.S. 93 would look like at Railroad Pass. Railroad Pass Casino is at left. If U.S. 93 is designated an interstate between Las Vegas and Phoenix, the bypass route would become part of the interstate, officials say.

By Danielle McCrea, Special to the Sun

Wednesday, Sept. 17, 2014 | 12:11 p.m.

Courtesy NDOT

This Nevada Department of Transportation graphic shows the route of the proposed Boulder City Bypass.

After a frustrating seven-month delay to allow for hundreds of tests of asbestos-tainted soil, construction of a bypass highway around Boulder City is back on track.

Officials with the Nevada Department of Transportation and the Regional Transportation Commission of Southern Nevada gave the green light after concluding workers could safely cut the highway through the hills around Boulder City because the asbestos, discovered by UNLV geologists in 2011, did not reach harmful levels. Construction is slated to begin in the spring, officials said today.

To play it safe, construction zones will be heavily watered to prevent asbestos from becoming airborne and exposing workers. Additionally, there will be continued soil testing and real-time air sampling and, if exposure levels become unacceptable, contactors can halt work and launch additional mitigation, NDOT Project Manager Tony Lorenzi said.

The news “is a relief to everyone,” said Boulder City Mayor Roger Tober. “While initially the asbestos discovery caused alarm, this is just good news. For the levels that are there, there will be some mitigation, but it’s going to be taken care of.”

The $490 million highway project, more than 10 years in the making, would wend around Boulder City so traffic can move smoothly between Las Vegas and Arizona. Until the bypass is built, tourists, truckers and commuters must use U.S. 93, which slices into town where traffic slows miserably on busy days.

The bypass is envisioned as the first link in Interstate 11, a proposed interstate highway connecting Phoenix and Las Vegas.

Testing conducted over the summer confirmed the presence of asbestos but concluded it was not at a threatening level.

The project will be conducted in two phases by NDOT and the RTC. Each agency conducted its own tests to meet their respective regulations.

“Phase 1 is what we are calling clean,” Project Manager Tony Lorenzi said.

The first phase, a 2.5-mile connector starting at U.S. 95 and heading easterly toward the Colorado River, is NDOT”s responsibility. Tests of 150 soil samples showed no asbestos concentrations higher than 0.25 percent, deeming them safe. The second phase — RTC’s 12.5-mile stretch that finishes the bypass to the east — involved testing of 461 samples for concentrations less than 1 percent. Fourteen samples tested above 1 percent.

These concentrations are standard for construction sites where there’s naturally occurring asbestos.

“The most important thing is the comfort of the public,” Lorenzi said. “We want them to know that construction will be done safely, in compliance with every agency. We’re doing it right.”

The asbestos findings will be discussed at an open house from 4:30 to 6:30 p.m. Thursday at Elaine K. Smith Center Building, 700 Wyoming St., Boulder City. Representatives from Boulder City, the Boulder City Chamber of Commerce, NDOT and the RTC will be there to discuss the project.